DC-DC converters are electrical devices used to convert direct current (DC) electrical power from one voltage level to another. They are widely used wherever batteries are the primary source of electric power and in many other applications as well. One such use is in power amplifiers (PA); and the present invention will be described in that context. However, it will be apparent that the invention may be practiced in numerous other contexts as well.
While the use of DC-DC converters for PA systems is increasing, in most cases a high value external inductor is used with slow switching speeds. As a result, the DC-DC converter is not fast enough to modulate the RF envelope or the RF ramp directly, but an additional load dropout (LDO) regulator in series with the switcher is used. This increases the system losses. In addition, the external inductor consumes valuable additional board space and prevents integration of the DC-DC converter in the PA module.